package com.hmdp.service.impl;

import com.hmdp.config.RedissonConfig;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private ISeckillVoucherService seckillVoucherService;
    @Resource
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));//设置资源获取位置
        SECKILL_SCRIPT.setResultType(Long.class);//设置返回类型
    }
    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    //线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    //初始化线程池
    private class VoucherOrderHandler implements Runnable{
        @Override
        public void run() {
            while (true){
                try {
                    //获取队列中的订单
                    VoucherOrder voucherOrder = orderTasks.take();//有元素才会继续往下执行,否则会停留阻塞
                    //创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常",e);

                }
            }
        }
        private void handleVoucherOrder(VoucherOrder voucherOrder) {
            //1.获取用户
            Long userId = voucherOrder.getUserId();
            //2.创建锁对象
            RLock lock = redissonClient.getLock("lock:order:" + userId);
            //3.获取锁;这里是为了防止redis出现问题导致线程不安全,虽然redis出问题的概率性很低
            boolean isLock = lock.tryLock();
            //4.判断是否成功
            if (!isLock){
                //获取锁失败,返回错误或重试
                log.error("不允许重复下单");
                return;
            }
            try{
                proxy.createVoucherOrder(voucherOrder);
            }finally {
                lock.unlock();
            }

        }
    }
    private IVoucherOrderService proxy;

    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户
        Long userId = UserHolder.getUser().getId();
        long orderId = redisIdWorker.nextId("order");
        //1.执行Lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),//传一个空集合
                voucherId.toString(), userId.toString(),String.valueOf(orderId)
        );
        //2.判断结果是否为0
        int r = result.intValue();
        //2.1不为0代表没有购买资格
        if (r != 0){
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        //3获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        //3返回订单id
        return Result.ok(orderId);
    }














    @Transactional(rollbackFor = Exception.class)
    public  void createVoucherOrder(VoucherOrder voucherOrder){
        //5.一人一单
        Long userId = voucherOrder.getUserId();
        Long voucherId = voucherOrder.getVoucherId();
        //5.查询订单
        int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder).count();
        //5.2判断是否存在
        if (count > 0) {
            log.error("用户已经购买过一次！");
        }
        //6.扣减库存
        boolean success = seckillVoucherService.update()
                .setSql("stock = stock -1")//set stock = stock -1
                .eq("voucher_id", voucherId)//where id =?
                .gt("stock", 0)//and stock>0?
                .update();//判断id是否相等
        if (!success) {
            log.error("库存不足！");
        }
        save(voucherOrder);
    }


    /**
     * 没有redis消息队列
     * @param voucherId
     * @return
     */
//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //获取用户
//        Long userId = UserHolder.getUser().getId();
//        //1.执行Lua脚本
//        Long result = stringRedisTemplate.execute(
//                SECKILL_SCRIPT,
//                Collections.emptyList(),//传一个空集合
//                voucherId.toString(), userId.toString()
//        );
//        //2.判断结果是否为0
//        int r = result.intValue();
//        //2.1不为0代表没有购买资格
//        if (r != 0){
//            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
//        }
//        //2.2 为0时有购买资格,把下单信息保存到阻塞队列
//        //2.3订单id
//        VoucherOrder voucherOrder = new VoucherOrder();
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        //2.4用户id
//        voucherOrder.setUserId(userId);
//        //2.5 代金券id
//        voucherOrder.setVoucherId(voucherId);
//        //2.6创建阻塞队列，保存到阻塞队列
//        orderTasks.add(voucherOrder);
//        //3获取代理对象
//        proxy = (IVoucherOrderService) AopContext.currentProxy();
//        //3返回订单id
//        return Result.ok(orderId);
//    }









//    @Transactional(rollbackFor = Exception.class)
//    public  Result createVoucherOrder(Long voucherId){
//        //5.一人一单
//        Long userId = UserHolder.getUser().getId();
//            //5.查询订单
//            int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
//            //5.2判断是否存在
//            if (count > 0) {
//                return Result.fail("用户已经购买过一次！");
//            }
//            //6.扣减库存
//            boolean success = seckillVoucherService.update()
//                    .setSql("stock = stock -1")//set stock = stock -1
//                    .eq("voucher_id", voucherId)//where id =?
//                    .gt("stock", 0)//and stock>0?
//                    .update();//判断id是否相等
//            if (!success) {
//                return Result.fail("库存不足！");
//            }
//
//            //7.创建订单
//            VoucherOrder voucherOrder = new VoucherOrder();
//            //7.1订单id
//            Long orderId = redisIdWorker.nextId("order");
//            voucherOrder.setId(orderId);
//            //7.2用户id
//            voucherOrder.setUserId(userId);
//            //7.3优惠券id
//            voucherOrder.setVoucherId(voucherId);
//            save(voucherOrder);
//            //7.返回订单id
//            return Result.ok(orderId);
//    }
//
//
//



//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //1.查询优惠券
//        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);
//        //2.判断秒杀是否开始
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())){
//            return Result.fail("秒杀尚未开始");
//        }
//        //3.判断秒杀是否结束
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())){
//            return Result.fail("秒杀已经结束");
//        }
//        //4.判断库存是否充足
//        if (voucher.getStock() < 1){
//            return Result.fail("库存不足！");
//        }
//        Long userId = UserHolder.getUser().getId();
//        //创建锁对象
////        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        //获取锁
//        boolean isLock = lock.tryLock();
//        if (!isLock){//采用反向逻辑，如果是判断成功的话需要嵌套
//            //获取失败
//            return Result.fail("一个人只能一单!!!");
//        }
//        try {
//            //因为该方法是直接this调用,不会经过代理对象，那么事务注解会失效，所以需要获取代理对象
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        } catch (IllegalStateException e) {
//            throw new RuntimeException(e);
//        }finally {
//            //释放锁
//            lock.unlock();
//        }
//    }


}





















































